w.WriteHeader(code)
	fmt.Fprintln(w, error)
}

// NotFound replies to the request with an HTTP 404 not found error.
func NotFound(w ResponseWriter, r *Request) { Error(w, "404 page not found", StatusNotFound) }

// NotFoundHandler returns a simple request handler
// that replies to each request with a “404 page not found” reply.
func NotFoundHandler() Handler { return HandlerFunc(NotFound) }

        Set<TestFile> dirs = []
        def pattern = Pattern.compile("Transformed " + Pattern.quote(from) + " to " + Pattern.quote(to) + " into (${outputDirPattern})")
        for (def line : stream.call().readLines()) {
            def matcher = pattern.matcher(line)
            if (matcher.matches()) {
                dirs.add(new TestFile(matcher.group(1)))
            }
        }
        return dirs
    }

// 3) If `is_stateless` is false and no ordering token is present, then we treat
//    the op conservatively which means that different op instances need
//    dependencies. This is realized by always returning the same string ("")
//    in this case. In fact, we could return any string here, as long as it is
//    the same string for all op instances without ordering tokens.